Background: Patient-reported outcome measures (PROMs) provide the patient’s perspective following total hip arthroplasty (THA), although differences between primary THA (pTHA) and revision THA (rTHA) remain unclear. Thus, we compared the Minimal Clinically Important Difference for Improvement (MCID-I) and Worsening (MCID-W) in pTHA and rTHA patients.
Methods: Data from 2,159 patients (1,995 pTHAs/164 rTHAs) who had completed Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form (HOOS-PS), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Short Form 10a (PF10a), PROMIS Global-Mental, or PROMIS Global-Physical questionnaires were analyzed. The PROMs and MCID-I/MCID-W rates were compared using statistical tests and multivariate logistic regressions.
Results: Compared to the pTHA group, the rTHA group had lower rates of improvement and higher rates of worsening for almost all PROMs, including HOOS-PS (MCID-I: 54 vs. 84%, P<0.001; MCID-W: 24 vs. 4.4%, P<0.001), PF10a (MCID-I: 44 vs. 73%, P<0.001; MCID-W: 22 vs. 5.9%, P<0.001), PROMIS Global-Mental (MCID-W: 42 vs. 28%, P<0.001), and PROMIS Global-Physical (MCID-I: 41 vs. 68%, P<0.001; MCID-W: 26 vs. 11%, P<0.001). Odds ratios supported rates of worsening following revision for the HOOS-PS (Odds Ratio (OR): 8.25, 95% Confidence Interval (CI): 5.62-12.4, P<0.001), PF10a (OR: 8.34, 95% CI: 5.63-12.6, P<0.001), PROMIS Global-Mental (OR: 2.16, 95% CI: 1.41-3.34, P<0.001), and PROMIS Global-Physical (OR: 3.69, 95% CI: 2.46-5.62, P<0.001).
Conclusion: Patients reported higher rates of worsening and lower rates of improvement following rTHA than pTHA, with significantly less score improvement and lower postoperative scores for all PROMs after revision. Most patients reported improvements following pTHA, with few worsening postoperatively.